为了解决 工具 起多个服务的时候端口被占用的情况。分享研究的代码片段。

// 检测port是否被占用function probe(port, callback) {    var server = net.createServer().listen(port)    var calledOnce = false    var timeoutRef = setTimeout(function () {        calledOnce = true        callback(false,port)    }, 2000)    timeoutRef.unref()    var connected = false    server.on('listening', function() {        clearTimeout(timeoutRef)        if (server)            server.close()        if (!calledOnce) {            calledOnce = true            callback(true,port)        }    })    server.on('error', function(err) {        clearTimeout(timeoutRef)        var result = true        if (err.code === 'EADDRINUSE')            result = false        if (!calledOnce) {            calledOnce = true            callback(result,port)        }    })}function server(_port){    var pt = _port || __port;    probe(pt,function(bl,_pt){        // 端口被占用 bl 返回false        // _pt：传入的端口号        if(bl === true){            // ssr(_pt)            server = http.createServer(connListener);            server = server.listen(parseInt(_pt, 10));            console.log("\n  Static file server running at" + "\n\n=> http://localhost:" + _pt + '\n');        }else{            server(_pt+1)        }    })}复制代码